truprecht :
I've changed motherboards without re-installing Windows 7 - it updated the drivers and was OK. But, it might not always work, and I think it's different now with UEFI BIOS. Probably can't hurt to try. If it doesn't work, then re-install.
I've found that stuff like that works depending on how closely related the chipsets on the motherboards are.
For example, upgrading from a Intel P35-based motherboard to a P45-based board would likely work (I've done this, from an Abit IP35-E to a Gigabyte EP45-UD3LR), but switching from Intel Z77 to AMD 990FX wouldn't.
However, there is also the legality involved in licensing, as SR-71 covered. I used a retail edition, so I would be covered.
Casey